Abstract:Single molecule-based electronic devices hold the potential for higher density and higher performance applications in medicine, sensing, computing and photovoltaics. Experimentally, metal-molecule-metal (MMM) junctions provide a system for measuring molecular electronic properties directly. We developed a computer controlled electromigration (CCE) process for creating nanogaps at room temperature which allows us to characterize a bare nanogap before putting a molecule into the nanogap. This is very different from other approaches used in the field where nanogaps are formed at low temperature with molecules already attached to the nanowire by employing a simple ramp up in voltage. Formation of nanogaps at room temperature requires CCE because an uncontrolled ramp up in voltage results in gap sizes greater than 100 nm and promotes metal particle formation. Additionally, we have adapted the computer controlled electromigration process to create nanogaps on electron transparent SiNx membranes for transmission electron microscope (TEM) imaging. TEM reveals that electromigrated Au electrodes consistently snap to a smallest gap size of approximately 4 nm and provides detailed information on the geometry of the nanogap.